OSX Lion upgrade screwed, can't use my mac

[Xer]

Hi guys how are you?

I just purchased Lion from the App store and upgraded, everything seemed fine at first.
I restarted my computer for some reason and when it finished the dock did not launch, neither does the wallpaper.
I can barely use the OS and I can't find the DMG file to do a reinstall.
I don't know what to do, please help me.
I'm attaching 2 pics so you can see what I'm talking about.
Also, the whole system runs so slow it's disgusting! and I'm using the latest 2.2 Macbook pro!

Thanks so much!